A microdialysis method that allows in situ studies of the action of various signals on lipolysis in adipose tissue was recently developed. The priciple objective of this study is to investigate the effects of hormones, neurotransmitters, and neuropeptides on regulations of fat cell metabolism in subcutaneous adipose tissue in vivo by measuring water soluble metabolites using this micro-dialysis technique. This investigation will provide better understanding on the regulation and metabolism of the fat cell and its association to whole body metabolism in humans. In the proposed study, the regulation of blood flow and metabolites of adipose tissues by hormones and neurotransmitters in three areas of the body, namely, breast, abdomen and thigh, will be examined.